<!DOCTYPE html>
<html lang="zh">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>仿照Jquery</title>
    <style>
        .red{
            color: red;
        }
        .blue{
            background-color: blue;
        }
        .green{
            color:green;
        }
    </style>
</head>
<body>
    <div class="test">hello</div>
    <div class="test1">
        <div class="child">child1</div>
        <div class="child">child2</div>
        <div class="child">child3</div>
    </div>
    <div class="test2">
        <div class="child">child1</div>
        <div class="child">child2</div>
    </div>
    <div class="test3">
        <div class="child">child1</div>
    </div>
    <script src="jquery.js"></script>
    <script src="main.js"></script>
</body>
</html>